On Thu, Jun 27, 2019 at 06:00:30PM +0100, fdmanana@xxxxxxxxxx wrote:
> From: Filipe Manana <fdmanana@xxxxxxxx>
>
> Test that if we clone a file with some large extents into a file that has
> many small extents, when the fs is nearly full, the clone operation does
> not fail and produces the correct result.
>
> This is motivated by a bug found in btrfs wich is fixed by the following
> patches for the linux kernel:
>
> [PATCH 1/2] Btrfs: factor out extent dropping code from hole punch handler
> [PATCH 2/2] Btrfs: fix ENOSPC errors, leading to transaction aborts, when
> cloning extents
>
> The test currently passes on xfs.
>
> Signed-off-by: Filipe Manana <fdmanana@xxxxxxxx>
> ---
> tests/generic/558 | 75 +++++++++++++++++++++++++++++++++++++++++++++++++++
> tests/generic/558.out | 5 ++++
> tests/generic/group | 1 +
> 3 files changed, 81 insertions(+)
> create mode 100755 tests/generic/558
> create mode 100644 tests/generic/558.out
>
> diff --git a/tests/generic/558 b/tests/generic/558
> new file mode 100755
> index 00000000..ee16cdf7
> --- /dev/null
> +++ b/tests/generic/558
> @@ -0,0 +1,75 @@
> +#! /bin/bash
> +# SPDX-License-Identifier: GPL-2.0
> +# Copyright (C) 2019 SUSE Linux Products GmbH. All Rights Reserved.
> +#
> +# FSQA Test No. 558
> +#
> +# Test that if we clone a file with some large extents into a file that has
> +# many small extents, when the fs is nearly full, the clone operation does
> +# not fail and produces the correct result.
> +#
> +seq=`basename $0`
> +seqres=$RESULT_DIR/$seq
> +echo "QA output created by $seq"
> +tmp=/tmp/$$
> +status=1 # failure is the default!
> +trap "_cleanup; exit \$status" 0 1 2 3 15
> +
> +_cleanup()
> +{
> + cd /
> + rm -f $tmp.*
> +}
> +
> +# get standard environment, filters and checks
> +. ./common/rc
> +. ./common/filter
> +. ./common/reflink
> +
> +# real QA test starts here
> +_supported_fs generic
> +_supported_os Linux
> +_require_scratch_reflink
> +
> +rm -f $seqres.full
> +
> +_scratch_mkfs_sized $((512 * 1024 * 1024)) >>$seqres.full 2>&1
> +_scratch_mount
> +
> +file_size=$(( 128 * 1024 * 1024 )) # 128Mb
> +extent_size=4096
What if the fs block size is 64k?
> +num_extents=$(( $file_size / $extent_size ))
> +
> +# Create a file with many small extents.
> +for ((i = 0; i < $num_extents; i++)); do
> + offset=$(( $i * $extent_size ))
> + $XFS_IO_PROG -f -s -c "pwrite -S 0xe5 $offset $extent_size" \
> + $SCRATCH_MNT/foo >>/dev/null
> +done
I wouldn't have thought that this would actually succeed on xfs because
you could lay extents down one after the other, but then started seeing
this in the filefrag output:
File size of /opt/foo is 528384 (129 blocks of 4096 bytes)
ext: logical_offset: physical_offset: length: expected: flags:
3: 17.. 17: 52.. 52: 1: 37:
4: 18.. 18: 67.. 67: 1: 53:
5: 19.. 19: 81.. 81: 1: 68:
6: 20.. 20: 94.. 94: 1: 82:
7: 21.. 21: 106.. 106: 1: 95:
8: 22.. 22: 117.. 117: 1: 107:
9: 23.. 23: 127.. 127: 1: 118:
10: 24.. 24: 136.. 136: 1: 128:
11: 25.. 25: 144.. 144: 1: 137:
12: 26.. 26: 151.. 151: 1: 145:
13: 27.. 27: 157.. 157: 1: 152:
14: 28.. 28: 162.. 162: 1: 158:
15: 29.. 29: 166.. 166: 1: 163:
16: 30.. 30: 169.. 169: 1: 167:
17: 31.. 32: 171.. 172: 2: 170:
18: 33.. 33: 188.. 188: 1: 173:
52, 67, 81, 94, 106, 117, 127, 136, 44, 151, 157, 162, 166, 169, 171...
+15 +14 +13 +12 +11 +10 +9 +8 +7 +6 +5 +4 +3 +2...
Hm, I wonder what quirk of the xfs allocator this might be?
> +
> +# Create file bar with the same size that file foo has but with large extents.
> +$XFS_IO_PROG -f -c "pwrite -S 0xc7 -b $file_size 0 $file_size" \
> + $SCRATCH_MNT/bar >>/dev/null
> +
> +# Fill the fs (for btrfs we are interested in filling all unallocated space
> +# and most of the existing metadata block group(s), so that after this there
> +# will be no unallocated space and metadata space will be mostly full but with
> +# more than enough free space for the clone operation below to succeed).
> +i=1
> +while true; do
> + $XFS_IO_PROG -f -c "pwrite 0 2K" $SCRATCH_MNT/filler_$i &> /dev/null
> + [ $? -ne 0 ] && break
> + i=$(( i + 1 ))
> +done
_fill_fs?
> +
> +# Now clone file bar into file foo. This is supposed to succeed and not fail
> +# with ENOSPC for example.
> +$XFS_IO_PROG -c "reflink $SCRATCH_MNT/bar" $SCRATCH_MNT/foo >>/dev/null
_reflink $SCRATCH_MNT/bar $SCRATCH_MNT/foo ?
--D
> +
> +_scratch_remount
> +
> +echo "File foo data after cloning and remount:"
> +od -A d -t x1 $SCRATCH_MNT/foo
> +
> +status=0
> +exit
> diff --git a/tests/generic/558.out b/tests/generic/558.out
> new file mode 100644
> index 00000000..d1e8e70f
> --- /dev/null
> +++ b/tests/generic/558.out
> @@ -0,0 +1,5 @@
> +QA output created by 558
> +File foo data after cloning and remount:
> +0000000 c7 c7 c7 c7 c7 c7 c7 c7 c7 c7 c7 c7 c7 c7 c7 c7
> +*
> +134217728
> diff --git a/tests/generic/group b/tests/generic/group
> index 543c0627..c06c1cd1 100644
> --- a/tests/generic/group
> +++ b/tests/generic/group
> @@ -560,3 +560,4 @@
> 555 auto quick cap
> 556 auto quick casefold
> 557 auto quick log
> +558 auto clone
> --
> 2.11.0
>
